Impression die forging method and apparatus

ABSTRACT

Disclosed is a method of impression die forging in which one or both of the opposed dies carry an even number of progressive die impressions on their face with the dies being identically paired. Each member of each impression pair is spaced equally on opposite sides of the center line of forging energy application (the center of the die face). The method requires simultaneous presentation of workpieces in both die impressions of at least one of the spaced impression pairs.

United States Patent [191 Dorton Nov. 20, 1973 4] IMPRESSION DIE FORGING METHOD AND [21] Appl. No.: 288,119

Primary Examiner-Lowell A. Larson Attorney--Maurice A. Weikart [5 7] ABSTRACT Disclosed is a method of impression die forging in which one or both of the opposed dies carry an even number of progressive die impressions on their face with the dies being identically paired. Each member of U-S. 72/374, each impression pair is paced equally on opposite :72/472 sides of the center line of forging energy application (the center of the face) The requires i- Fleld 0 Search multaneous presentation of workpieces in die in]. 72/374 375, 404, 472, 376 pressions of at least one of the spaced impression pairs. [56] References Cited UNITED STATES PATENTS 6 Claims 10 Drawing Figures 680,219 8/1901 Blakeslee 72/472 1,373,571 4/1921 Smith 72/404 mimgnuuvm ms SHEET EC? 3 IMPRESSION DIE FORGING METHOD AND APPARATUS BACKGROUND OF THE INVENTION In forging operations using drop forge hammers, for example, stresses on the forging hammer and its supporting structure are considerable. However, with anvil type hammers approximately percent of the total energy of the hammer blow is absorbed into the anvil and foundation, the other 80 percent being useable energy for plastic deformation of the workpiece or billet. To efficiently use this available energy and to lengthen the service life of the forging equipment with minimum maintenance, it is important to minimize, so far as possible, any lateral or sideward force components of the forging blows on the dies and their supporting structure. While the advantages of the method herein described are related, in the description, particularly to a board hammer, it will be understood that the method is equally applicable to forging operations conducted on forging presses, steam hammers, counterblow hammers and the like.

Conventionally, the dies utilized in forging opera-- tions are provided with a progressively formed series of die impressions. These may include an edger, blocker, bender and finishing impressions. A single billet is moved, either manually by tongs or automatically, consecutively through the die impressions, receiving one or more forging blows at each station until the workpiece leaves the finish impression substantially formed and ready for trimming of any flash formed in the forging operation. Since only one die impression can be positioned under the center line of forging energy application, that is, centered under the ram in a drop-forging operation, when the workpiece is in any of the remaining die impressions, the hammer blow will produce eccentric loading of the forging apparatus and undesirable lateral forces on the ram guides and frame and on the dies themselves.

The concept of the present invention envisages simultaneously presenting at least two workpieces in identically paired die impressions which are equally spaced on opposite sides of the center of forging energy application. The dies are provided with an even number of impressions which are identically paired and spaced so that with any one hammer blow the force moments generated by the forging resistance about the center line of forging energy application are balanced. The two workpieces are moved together through the progressively formed pairs of die impressions, that is for example, from the two edger impressions to the two blocker impressions and finally to the two finish impressions.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a conventional board hammer used in drop forging operations.

FIG. 2 is a fragmentary, enlarged side view of the upper (hammer) die and lower (anvil) die utilized in the present invention.

FIG. 3 is a top plan view of the lower die shown in FIG. 2, the workpieces being shown in broken lines.

FIG. 4 is a fragmentary side sectional view showing one of the workpieces after completion of the blocking operation.

FIG. 5 is a fragmentary side sectional view of one of workpieces at the completion of the finishing operation.

FIG. 6 is a top plan view of a workpiece shown at the completion of the edging operation.

. FIG. 7 is a top plan view ofa workpiece at the completion of the blocking operation.

FIG. 8 is a top plan view of a workpiece at the completion of the finish operation.

FIG. 9 is a schematic enlarged view of the ram and dies of a board hammer illustrating the lateral forces produced by the non-concentric blows of the hammer in conventional forging operations.

FIG. 10 is a top plan view of a modified form of arrangement of the impressions in a lower die.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates a conventional drop hammer forging apparatus referred to as a board hammer and includes supporting structure 10, and operating head 1 l, a ram 12 and a sowblock l3. Secured to the ram is an upper or hammer die 14 which registers with a lower or anvil die 16. Depression of the treadle 17 allows the hammer to fall applying a forging blow to the workpiece (not shown) which is either manually positioned or automatically positioned in the die impressions 16a in the lower die. It will be understood that the upper die 14 has registering and matching impressions. It is conventional to provide the die faces with a series of progressive impressions or cavities and a workpiece is moved from one impression to the next after one or more hammer blows have been delivered to the work forming it to the extent determined by the die impression. As may be seen in FIG. 9 when a single workpiece 21 is positioned in one of the progressive impressions 22 in the lower die 23 the application of a forging blow by the ram schematically illustrated at 24 and comparable to the ram 12 of FIG. 1, lateral forces, indicated by arrows 26 will act on the ram, dies and supporting structure. Elimination of these lateral forces is the objective of the method andapparatus of the present invention.

Referring to FIGS. 2 and 3, there is shown upper and lower dies 31 and 32, which are comparable to and occupy the same place in the forging machinery as the dies 16 and 14 of FIG. 1. The faces 31a and 32a of the dies are provided with an even number of progressive die impressions which are identically paired. A pair of die impressions 33 (indicated also as station 1 in FIG. 2) are edger impressions and, as may best be seen in FIG. 2, are equally spaced from the center of the die face 35 which is also the center line of forging energy application of the forging apparatus. The die impressions function to form a workpiece 34 (FIG. 6), the unformed end 34a of the workpiece serving as a tong hold permitting the necessary manipulation of the workpiece through the various forging operations.

The identical die impressions 36 in the face of the lower die 31 (identified also as station 2 in FIG. 2) serve to further form the workpiece after the edging operation at impressions 33 has been completed. The workpiece, after this blocking operation at impressions 36 appears as shown in FIG. 7. From FIG. 7 and 8 it will be evident that the workpiece is being forged, as an example, into five gear blanks having hub portions 37. It will be understood that FIG. 7 shows the same workpiece 34 as shown in FIG. 6 but after the blocking operation. The workpiece at the blocking operation appears in cross section as shown in FIG. 4.

Next the two workpieces formed into the configuration shown in FIG. 7 are removed from the identical die impressions 36 and are transferred to the finish die impressions 38 (FIG. 2). These die impressions 38 are also identified as station 3 in FIG. 2. The workpiece at the conclusion of the finish operation at station 3 is formed into the configuration shown in FIGS. and 8, these finish impressions having a flash land 41 and gutter 42 to accomodate the flash 43 resulting from the forging process as is conventional, this flash being subsequently trimmed from the forged part.

As will be evident from FIG. 2, the upper die 32 has registering duplicate impressions. Two workpieces 34 are shown in broken lines in place in the blocking impressions 36 and it will be understood thatthe method of the present invention envisages moving two workpieces simultaneously from the station 1 to the station 2 (the workpieces shown there in FIG. 3) and finally to station 3, the finish impressions.

The concept of arranging the die impressions in pairs, each impression equally space opposite its twin diametrically across the center of the die or the center of forging energy application, and always simultaneously presenting workpieces in both die impressions of at least one of the spaced impression pairs, insures that a workpiece is on each side of the center of the die and that the hammer blow is concentric with relation to the anvil or base of the forging apparatus and insuring that the unbalanced condition illustrated in FIG. 9 cannot occur.

FIG. illustrates a modified form of die impression arrangement in which the face 51 of the die 52 is provided with an even number (four) die impressions 53, 54, 55 and 56. The die impressions are arranged symetrically about the center 57 of the face of the die, impressions 53 and 55 being identical and impressions 54 and 56 being identical. workpieces may be simultaneously presented in the die impressions 53 and 55, for example, for the accomplishment of a blocking operation, and after this operation is completed the two workpieces may be transferred to the die impressions 54 and 56 for a finish operation. It will be noted that, as in the case of the die of FIG. 3, the force moments generated by the forging resistance offered by the workpieces in the die impressions are balanced about the center line of forging energy application 57.

It will be understood that it is conventional to bring a workpiece to its final configuration by means of a plurality of progressive die impressions and that edging,

blocking and finishing are commonly included in a single set of dies. However, the method of the present invention utilizes an even number of impressions which are paired identically and the members of the pair are equally spaced from the center of application of the forging energy. This assures balance in the forging equipment during the forging operation and permits maximum ram impact and minimizes undesirable side thrusts and pressures during forging.

I claim:

1. A method of impression die forging in which blows by opposed registering dies shape metal workpieces by plastic deformation, said method comprising providing a forging apparatus with two opposed dies at least one die having an even number of progressive die impressions therein, said die impressions being identically paired with each pair spaced upon the die face so that the force moments generated by the forging resistance offered by workpieces in said die impressions are balanced about the center line of forging energy application of the forging apparatus, and simultaneously presenting workpieces in both die impressions of at least one of said spaced impression pairs during the forging operation to minimize lateral forces resulting from the metal forming blows.

2. The method claimed in claim 1 in which both of said two opposed dies are provided with said identically paired die impressions.

3. The method claimed in claim 1 in which said identically paired die impressions are rectilinearly aligned across the die face with each impression being spaced from the center of the die face a distance equal to the spacing of its twin.

4. The method claimed in claim 1 in which said identically paired die impressions are symetrically arranged about the center of the die face with each die impression being diametrically opposite its twin across the center of the die face and spaced from the die face center a distance equal to that of its twin.

5. A die for impression die forging having a face carrying an even number of progressive die impressions therein, said die impressions being identically paired, each die impression being diametrically opposite its twin across the center of the die face and spaced from the die face center a distance equal to that of its twin.

6. A die for impression die forging as claimed in claim 5 in which said die impressions are rectilinearly aligned across the die face with each impression being spaced from the center of the die face a distance equal to the spacing of its twin. 

1. A method of impression die forging in which blows by opposed registering dies shape metal workpieces by plastic deformation, said method comprising providing a forging apparatus with two opposed dies at least one die having an even number of progressive die impressions therein, said die impressions being identically paired with each pair spaced upon the die face so that the force moments generated by the forging resistance offered by workpieces in said die impressions are balanced about the center line of forging energy application of the forging apparatus, and simultaneously presenting workpieces in both die impressions of at least one of said spaced impression pairs during the forging operation to minimize lateral forces resulting from the metal forming blows.
 2. The method claimed in claim 1 in which both of said two opposed dies are provided with said identically paired die impressions.
 3. The method claimed in claim 1 in which said identically paired die impressions are rectilinearly aligned across the die face with each impression being spaced from the center of the die face a distance equal to the spacing of its twin.
 4. The method claimed in claim 1 in which said identically paired die impressions are symetrically arranged about the center of the die face with each die impression being diametrically opposite its twin across the center of the die face and spaced from the die face center a distance equal to that of its twin.
 5. A die for impression die forging haviNg a face carrying an even number of progressive die impressions therein, said die impressions being identically paired, each die impression being diametrically opposite its twin across the center of the die face and spaced from the die face center a distance equal to that of its twin.
 6. A die for impression die forging as claimed in claim 5 in which said die impressions are rectilinearly aligned across the die face with each impression being spaced from the center of the die face a distance equal to the spacing of its twin. 